Cure for love: Chemical cures for the lovesick

ROSES are red, violets are blue, when you reject me, what can I do? As we discover more about love's neural basis, we are getting closer to a way of curing its ills.

While many might be wary of a chemical cure for heartbreak, there is an argument that such anti-love solutions could help people struggling with suicidal or delusional thoughts because of unrequited love, or those in the clutches of unrelenting grief. The morals of the use and misuse of such drugs are complex (see "Cure for love: Should we take anti-love drugs?"), but ethics aside, what could a cure for love look like?

First things first: what is love? For Shakespeare, it "is an ever-fixed mark, that looks on tempests and is never shaken". For neuroscientists, it's less poetic: a neurobiological phenomenon that falls into three subtypes: lust, attraction and attachment – all of which increase our reproductive and parental success.

Each aspect is grounded in a suite of overlapping chemical systems in the brain. There are ways to diminish each of them, says Helen Fisher at Rutgers University in New Jersey, but they aren't always palatable.

Take lust. Ever found yourself obsessing over the tiniest details of a person? Their hair, say, or the number of kisses in a text? This tunnel vision resembles some of the symptoms of obsessive compulsive disorder, so Donatella Marazziti at the University of Pisa in Italy, compared the brains of 20 people in the first throes of love with those of 20 people with OCD.

Both groups had unusually low levels of a protein that transports serotonin – a hormone involved in regulating mood – around the brain. Retesting the lovers a year later revealed that their serotonin levels had increased, and that they no longer reported an obsessive focus on their partners.

Drugs that boost serotonin can offer relief to people with OCD, so it's reasonable to think that they could also help to dampen lustful feelings. These drugs include antidepressants called selective serotonin reuptake inhibitors, which are known to blunt extreme emotions and make it harder to form romantic bonds. This is an unwanted side effect for people with depression, but for those seeking to detach from someone, it could be welcome.

What if it's not lust but a lasting bond you want severed? Several chemicals play a role in helping us form attachments, and animal studies are showing how we could manipulate them to do just that.

The prairie vole is famously monogamous – it forms one life-long bond. However, when Larry Young at Emory University in Atlanta, Georgia, injected female voles with a drug that blocked either dopamine or oxytocin, they became polygamous. "This suggests you might be able to block oxytocin and sever a long-term attachment," says Young.

But oxytocin is important for all relationships, not just romantic love. You might cure your broken heart, but is it worth impairing all your other relationships?

Young's team has also shown that blocking corticotropin-releasing factor (CRF), a hormone involved in the stress response, stops the depressive behaviour that prairie voles exhibit when their partner dies. Young doesn't recommend blocking CRF for unrequited love, but he says it could be helpful to relieve the depression that comes with persistent grief.

Since love shares some of the neural underpinnings with addiction, you will need to replace your fix of oxytocin or dopamine. You can do this without popping a pill, says Young. Exercise ramps up dopamine levels, and bodily contact and social interaction can raise oxytocin.

Should we expect to see quick-fix solutions offered off label or in some anti-love black market? "I think there would be a real market, but I certainly don't recommend it," says Young.

Ultimately, time is the answer, says Fisher. Her team is the first to study the neural mechanisms involved as love fades away. She has found that people who are pining after a lost love have greater brain activity in the ventral pallidum, involved in attachment, than people who were happily in love. This activity diminished over time, suggesting that their attachment also waned.

Other groups are trying to help people with post-traumatic stress disorder replace a memory with another that is less emotionally fraught. "Hypothetically, you could imagine a similar therapy being used to dampen the memory of love," says Fisher. One day it might even be possible to use brain stimulation to decrease activity in the ventral pallidum, to speed up the healing effects of time, she says.

Until then, it seems what your mother told you about heartbreak still rings true: you can't beat time and a little love from someone new.

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Love has the same neural base as addiction (Image: Benjamin Bechet/Picturetank)